Now, why wasn't the bearer of the moonstone there?
One hundred years is quite a long time. Plenty of time for a civilization or group of people to die out.

Nami's moonstone was delivered by the same people Diana now represents. Every hundred years, they'd deliver the moonstone to the Marai for the abyssal pearl (probably for a survival reason of their own, though if so, that doesn't seem to have worked.)
This is my main point, though - as the Moon's people are now gone, save for Diana, they obviously cannot make the annual trade.

And, since the moon people... Read More